diff --git a/klippy/clocksync.py b/klippy/clocksync.py
index fdd6cbcd..a5ddf619 100644
--- a/klippy/clocksync.py
+++ b/klippy/clocksync.py
@@ -113,7 +113,7 @@ class ClockSync:
         pred_stddev = math.sqrt(self.prediction_variance)
         self.serial.set_clock_est(new_freq, self.time_avg + TRANSMIT_EXTRA,
                                   int(self.clock_avg - 3. * pred_stddev))
-        self.clock_est = (self.time_avg - self.min_half_rtt,
+        self.clock_est = (self.time_avg + self.min_half_rtt,
                           self.clock_avg, new_freq)
         #logging.debug("regr %.3f: freq=%.3f d=%d(%.3f)",
         #              sent_time, new_freq, clock - exp_clock, pred_stddev)